SMART-1 is the first of ESA’s Small Missions for Advanced Research in Technology. It is heading for the Moon using a solar-electric propulsion system and carrying a range of miniaturised instruments. As well as testing new technology, SMART-1 will make the first comprehensive inventory of key chemical elements in the lunar surface. It will also investigate the theory that the Moon was formed following the violent collision of a smaller planet with Earth, 4500 million years ago.